1. Field of the Invention
The present invention relates to pre-mix compositions for use in plant growth media and to plant growth media having such pre-mixes incorporated therein as well as to processes for producing such plant growth media. More particularly, it relates to blended or mixed coconut coir pith/surfactant compositions formulated to be incorporated into plant growth media to enable enhanced wetting thereof, while the media are being used, and re-wetting, if the media have dried out and to plant growth media having such pre-mixed compositions containing coconut pith (xe2x80x9ccoirxe2x80x9d) and selected surfactants incorporated therein to promote new and improved wetting and re-wetting characteristics therein and to processes for producing such plant growth media.
2. Description of Related Art
Examples of organic matter suitable for use as plant growth media in the present invention include peat moss, sphagnum peat, sedge peat (also known as xe2x80x9cFloridaxe2x80x9d peat), potting soils such as top soils,. composted yard waste (e.g., composted grass clippings, leaves, mulch, hedge trimmings and the like); wood and lignocellulose derivatives (e.g., wood chips, wood pulp such as fluffed pulp, extruded wood, pressure treated wood and the like); composted bark (e.g., pine bark and other barks); agricultural waste products such as the remnants produced, for example, during harvesting of grains and beans including materials such as straw and grain husks; animal waste products such as cattle, pig, chicken and/or horse manure; livestock processing by-products such as blood meal and the like; organic waste materials resulting from treated municipal sewage sludge; organic waste materials resulting from treated landfill materials comprising residential and commercial food, paper and yard waste.
Examples of the foregoing types of plant growth media, and processes for obtaining them, are well known in the art. In this regard, reference may be had to disclosures such as those included in U.S. Pat. Nos. 4,088,528; 4,185,680; 5,269,634; 5,413,618; 5,542,962; 5,567,220; 5,976,211; 5,900,038; European Patent EPO 923 854; and PCT applications WO 99/57079 and WO 99/57080, all of which are incorporated herein by reference.
Relatively recently, it has been recognized that coconut coir pith material provides an excellent growing medium for plants and it has been suggested that coconut coir pith could provide an effective alternative to previously standard growing media such as peat moss. Coconut coir pith is very similar to sphagnum peat moss in appearance having a light to dark brown color and consisting primarily of particles in the size range of 0.2-2.0 mm (75-90%). Unlike sphagnum peat, however, there are no sticks or extraneous matter in the coconut coir pith. Furthermore, sphagnum peat moss has a density of about 7 lbs/cu ft when fluffed (30-50% moisture content) whereas coir pith is much denser (i.e., about 43 lbs/cu ft at about 20% moisture content when compressed at a ratio of 5:1 on volume to volume basis and about 25 lbs/cu ft when fluffed and having a 50-55% moisture content).
Additional analysis of coconut coir pith in comparison with sedge peat and sphagnum peat products has indicated that coconut coir pith has superior structural stability because of the high lignin to cellulose content of the pith which prevents oxidation and shrinkage as compared with peat moss which has a high cellulose to lignin content.
Normally, coconut coir pith to be used as a plant growth medium is prepared by collecting aged pith from existing waste dumps or newly processed pith and drying the material to a 20% moisture content and then compressing the pith into bricks at a compression ratio of about 5:1 (v/v). These compressed bricks can then be expanded by adding water at about 80% moisture content although some mechanical agitation is required in order to increase the output of the fluffed xe2x80x9coutturnedxe2x80x9d coir pith. This mechanical agitation requirement presents a disadvantage in processing coir pith as it presents an inconvenience and expense for growers and other end users of the product. A further disadvantage in the processing of coir pith as a plant growth medium is that, unlike compressed bales of peat moss which can be readily fluffed or outturned to yield a desirable fluffed product, coir pith takes considerably more time to be fluffed or xe2x80x9coutturnedxe2x80x9d.
Accordingly, it has been well known in the art to combine peat moss and coir pith in a non-compressed form. Such non-compressed mixtures of coir and peat moss are produced by initially decompressing bricks of compressed coir pith and bales of compressed peat moss to provide separate fluffed coir pith and fluffed peat moss raw materials. Then, the already fluffed materials are mixed together for distribution as a xe2x80x9cloose-fillxe2x80x9d product containing the decompressed, fluffed mixture of coir pith and peat moss. The fluffed products produced in this manner have been demonstrated to provide better media for growing plants than the media provided by coir pith or peat moss alone.
Certain processing difficulties observed with coir when used alone, as well as commercial limitations of loose fill mixtures of non compressed coir and peat moss, were successfully addressed in commonly assigned Kusey et al U.S. Pat. No. 6,189,260 entitled xe2x80x9cCompressed Mixtures of Coconut Coir Pith and Peat Moss and Processes for the Preparation Thereofxe2x80x9d, which patent is incorporated herein by reference and made a part hereof. Also, U.S. Pat. No. 6,189,260 disclosed that a surprising improvement in fluffed yield can be achieved when coir pith and peat moss, under controlled moisture conditions, are first compressed to form a baled product, and then decompressed via fluffing or outturning for ultimate use as a growth medium. In particular, U.S. Pat. No. 6,189,260 disclosed that decompression of a compressed coir/peat moss blend yields a final volume of fluffed product that is unexpectedly greater than the sum of the individual volumes of coir and peat moss used to produce the initial pre-compressed blend.
Thus, the use of coconut coir pith as a plant growth medium per se is known in the art. Also, as described in co-pending, commonly assigned Kusey et al U.S. patent application Ser. No. 09/768,169, entitled xe2x80x9cCompressed Blends of Coconut Coir Pith and Non-Coir, Non-Peat Materials and Processes for the Production Thereofxe2x80x9d, the use of coconut coir pith blended with either peat moss or a variety of other soil enhancing non-coir/non-peat ingredients (both organic and inorganic) have been demonstrated to provide excellent media for growing plants and the like.
In addition, it has been known heretofore to incorporate surfactants, often called wetting agents, into plant growth media such as potting media to aid in wetting of the growth media. However, significant problems have been encountered when such surfactants or wetting agents have been incorporated into growth media or potting media. That is, if the surfactant treated plant growth medium is dried out, for example, as a result of the storage of the treated growth medium for an extended period of time before use, the efficacy of the surfactant declines so that the growth media cannot be effectively re-wet after such time period. Also, it has been found that the effectiveness of a surfactant as a wetting agent to maintain the moisture content of growth media tends to disadvantageously decline over time once the growth media is in use.
In view of these problems, a need has been recognized in the horticultural arts for more effective and efficient compositions to be used to treat plant growth media in order to provide new and improved wetting and re-wetting characteristics in the treated growth media (i.e., to maintain the moisture content of the plant growth media over a period of time up to several months after application and/or to enable the growth media to be effectively wet after the plant growth media dries out); for processes to produce such growth media which exhibit new and improved wetting and re-wetting characteristics including an enhanced ability to be re-wet after they have been dried out, particularly as a result of storage or the like; and for treated growth media which demonstrate the foregoing advantageous characteristics.
Accordingly, it is a general object of the present invention to provide compositions for treating plant growth media to promote improved wetting and re-wetting thereof. In particular, it is a primary object of the present invention to provide premix compositions containing coconut coir pith and selected horticulturally acceptable surfactants or wetting agents for use in treating plant growth media.
A further object of the invention is to provide processes for producing plant growth media by incorporating of mixtures of coconut coir pith and horticulturally acceptable surfactants therein in sufficient amounts to enable the treated growth media to exhibit new and improved wetting and re-wetting characteristics, particularly after being dried out
Another important object of this invention is to provide plant growth media having mixtures of coconut coir pith and horticulturally acceptable surfactants incorporated therein in amounts sufficient to enable effective and efficient wetting and re-wetting of the growth media during use and/or after the growth media has become dried out.
These and other objects will become apparent hereinafter to those skilled in the art.
We have found that the foregoing and other objects as well as further improvements over the prior art of the present invention may be achieved by forming a pre-mix composition containing coconut coir pith (sometimes referred to herein as xe2x80x9ccoirxe2x80x9d) and a horticulturally acceptable surfactant, either ionic or non-ionic in nature, in a predetermined percent by weight of the surfactant to the total weight of the pre-mix composition. Then, in accordance with the present invention, the pre-mix composition is incorporated into a suitable plant growth medium such as the above-discussed blends of coconut coir pith and peat moss and blends of coconut coir pith and non-peat materials. Other common plant growth media which may also be used herein include peat moss, coconut coir pith, top soil, sphagnum peat, perlite, vermiculite, styrofoam and the like and composted organic materials such as bark, lignocellulites and the like to aid in wetting of the growth or potting media in an amount sufficient to enable effective and cost efficient wetting and re-wetting of the growth medium during use and/or after the growth medium has become dried out, for example, as a result of storage of the growth medium over an extended period of time.
Thus, in one aspect, the present invention is directed to a pre-mix composition for treating a plant growth medium to promote improved wetting and re-wetting thereof comprising a mixture of coconut coir pith and a horticulturally acceptable surfactant.
In a further aspect, the present invention provides a process for treating a plant growth medium comprising incorporating a pre-mixed blend of coconut coir pith and a horticulturally acceptable surfactant into the plant growth medium in an amount sufficient to promote improved wetting of the plant growth medium during use, before it becomes dried out, and to enable rewetting of the plant growth medium after it has dried out.
In a still further aspect of this invention, a plant growth medium is provided having a pre-mixed blend of coconut coir pith and a horticulturally acceptable surfactant incorporated therein in an amount sufficient to promote improved wetting of the plant growth medium during use, before it becomes dried out, and to enable re-wetting of the plant growth medium after it has dried out.
Accordingly, the present invention offers a number of significant advantages over the prior art. For example, the present invention enables solution of the significant problem that has been encountered concerning the decline in re-wetting efficacy which has been found to occur in plant growth media treated with prior surfactants/wetting agents which have been stored before use for long periods of time. Also the present invention enables solution of another significant problem that has been encountered concerning the decline in the continued wetting effectiveness of prior surfactants/wetting agent once in use.